In medicine, sutures have long been used to close wounds. More recently, adhesive closures have been introduced that can effectively close some types of wounds without inflicting the additional injury inherent in suturing. These adhesive closures have a backing to provide solid structure, and have an adhesive layer for adhering to the skin. There are two main criteria that must be reconciled in a successful design for these products: reliable adhesion to the skin, even when the wound is adjacent to a joint; and good performance in keeping the wound edges in proximity to each other.
One approach is to use a non-woven web as the basic backing, and to reinforce this material with strong fibers in the longitudinal, or cross-wound, direction. The main substance of the backing can bend with the skin as the patient moves, and the reinforcing fibers strengthen the lightweight backing so that the structure can resist wound edge separation. This backing is combined with a strong skin adhesive over the entire skin contacting surface. The strength of the reinforcing fibers, combined with their secure anchorage immediately adjacent to the wound edges provides excellent security against wound separation. For example, STERI-STRIPS wound closures, commercially available from Minnesota Mining and Manufacturing Company of St. Paul, Minn., are constructed in this way.
More recently, an improvement has been developed providing a wound closure including a wound bridging portion that has sufficient dimensional stability to hold the wound edges in proper alignment, even in the face of substantial stretching of the wound closure as a whole. The wound bridging portion is dimensionally stable where it is most needed, i.e., directly over the wound. The remainder of the wound closure is preferably substantially more extensible and elastic than the wound bridging portion to improve conformability and adhesion of the wound closure to the patient. More specifically, the wound closure has an adhesive for adhering the wound closure to skin, opposing elastomeric end portions, and a wound bridging portion between the end portions. The wound closure is constructed such that it recovers at least 85% after being stretched 30%, and such that the wound bridging portion stretches less than the end portions when subjected to the same force. In this way, the wound bridging portion tends to maintain the wound closed against forces generated by stretching of skin. Such a wound closure is disclosed in copending U.S. patent application Ser. No. 09/671,129 filed Sep. 27, 2000 and entitled CONFORMABLE ADHESIVE WOUND CLOSURES.
A different strategy for achieving adhesion to the skin and resistance to forces tending to open the wound edges is disclosed in U.S. Pat. No. 5,259,835 (Clark et al.). In that reference, a wound closure is provided employing a porous bonding member which receives a flowable adhesive capable of providing long-term wound support. In particular, cyanoacrylates are mentioned as being suitable for the flowable adhesive. A disadvantage of that system is that once the porous bonding member has received the flowable adhesive, and the adhesive has bonded to the skin, it becomes a rigid unit which can cause skin irritation along its edges as body movement flexes the skin against those edges.
Another group of adhesives which have utility for skin contacting application is disclosed in U.S. Pat. No. 6,383,502 (Dunshee et al.). These substances have good skin compatibility, and are hydrophobic so that they tend not to remain in the interior of wounds. However, their tensile strength is only sufficient for, e.g. closing or sealing skin cracks, not for holding major wounds closed against the range of motion skin is normally subjected to.